Thoughts: time warp to 2012

15
Nov

Node.js itself is blocking, only its I/O is non-blocking

I've recently been getting my feet wet, playing around with Node.js (yes, I know – what took me so long?). I'm having a lot of fun, learning new technologies by the handful. It's all very exciting.

I just thought I'd stop for a minute, however, to point out one important detail of Node.js that had me confused for a while, and that seems to have confused others, too. More likely than not, the first feature of Node.js that you heard about, was its non-blocking I/O model.

Now, please re-read that last phrase, and re-read it carefully. Non. Blocking. I/O. You will never hear anywhere, from anyone, that Node.js is non-blocking. You will only hear that it has non-blocking I/O. If, like me, you're new to Node.js, and you didn't stop to think about what exactly "I/O" means (in the context of Node.js) before diving in (and perhaps you weren't too clear on "non-blocking", either), then fear not.

What exactly – with reference to Node.js – is blocking, and what is non-blocking? And what exactly – also with reference to Node.js – is I/O, and what is not I/O? Let me clarify, for me as much as for you.

08
Nov

Batch updating Drupal 7 field data

On a number of my recently-built Drupal sites, I've become a fan of using the Computed Field module to provide a "search data" field, as a Views exposed filter. This technique has been documented by other folks here and there (I didn't invent it), so I won't cover its details here. Basically, it's a handy way to create a search form that searches exactly the fields you're interested in, thus providing you with more fine-grained control than the core Drupal search module, and with much less installation / configuration overhead than Apache Solr.

On one such site, which has about 4,000+ nodes that are searchable via this technique, I needed to add another field to the index, and re-generate the Computed Field data for every node. This data normally only gets re-generated when each individual node is saved. In my case, that would not be sufficient - I needed the entire search index refreshed immediately.

The obvious solution, would be to whip up a quick script that loops through all the nodes in question, and that calls node_save() on each pass through the loop. However, this solution has two problems. Firstly, node_save() is really slow (particularly when the node has a lot of other fields, such as was my case). So slow, in fact, that in my case I was fighting a losing battle against PHP "maximum execution time exceeded" errors. Secondly, node_save() is slow unnecessarily, as it re-saves all the data for all a node's fields (plus it invokes a bazingaful of hooks), whereas we only actually need to re-save the data for one field (and we don't need any hooks invoked, thanks).

In the interests of both speed and cutting-out-the-cruft, therefore, I present here an alternative solution: getting rid of the middle man (node_save()), and instead invoking the field_storage_write callback directly. Added bonus: I've implemented it using the Batch API functionality available via Drupal 7's hook_update_N().

17
Oct

How compatible are the world's major religions?

There are a tonne of resources around that compare the world's major religions, highlighting the differences between each. There are some good comparisons of Eastern vs Western religions, and also numerous comparisons of Christianity vs non-Christianity.

However, I wasn't able to find any articles that specifically investigate the compatibility between the world's major religions. The areas where different religions are "on the same page", and are able to understand each other and (in the better cases) to respect each other; vs the areas where they're on a different wavelength, and where a poor capacity for dialogue is a potential cause for conflict.

I have, therefore, taken the liberty of penning such an analysis myself. What follows is a very humble list of aspects in which the world's major religions are compatible, vs aspects in which they are incompatible.

28
Aug

How close is the European Union to being a federation?

There has been considerable debate over the past decade or so, regarding the EU and federalism. Whether the EU is already a federation. Whether the EU is getting closer to being a federation. Whether the EU has the intention of becoming a federation. Just what the heck it means, anyway, to be a federation.

This article is my quick take, regarding the current status of the federal-ness of the EU. Just a simple layman's opinion, on what is of course quite a complex question. Perhaps not an expert analysis; but, hopefully, a simpler and more concise run-down than experts elsewhere have provided.

19
Aug

Syria, past and present: mover and shaken

For the past few weeks, the world's gaze has focused on Syria, a nation currently in the grip of civil war. There has been much talk about the heavy foreign involvement in the conflict — both of who's been fuelling the fire of rebel aggression, and of who's been defending the regime against global sanctions and condemnation. While it has genuine grassroots origins – and while giving any one label to it (i.e. to an extremely complex situation) would be a gross over-simplification — many have described the conflict as a proxy war involving numerous external powers.

Foreign intervention is nothing new in Syria, which is the heart of one of the most ancient civilised regions in the world. Whether it be Syria's intervention in the affairs of others, or the intervention of others in the affairs of Syria – both of the above have been going on unabated for thousands of years. With an alternating role throughout history as either a World Power in its own right, or as a point of significance to other World Powers (with the latter being more often the case), Syria could be described as a serious "mover and shaken" kind of place.

This article examines, over the ages, the role of the land that is modern-day Syria (which, for convenience's sake and at the expense of anachronism, I will continue to refer to as "Syria"), in light of this theme. It is my endeavour that by exploring the history of Syria in this way, I am able to highlight the deep roots of "being influential" versus "being influenced by" – a game that Syria has been playing expertly for millennia – and that ultimately, I manage to inform readers from a new angle, regarding the current tragic events that are occurring there.

18
Jun

Israel's new Law of Return

Until a few days ago, I had no idea that Israel is home to an estimated 60,000 African refugees, the vast majority of whom come from South Sudan or from Eritrea, and almost all of whom have arrived within the past five years or so. I was startled as it was, to hear that so many refugees have arrived in Israel in such a short period; but I was positively shocked, when I then discovered that Israel plans to deport them, commencing immediately. The first plane to Juba, the capital of South Sudan, left last night.

South Sudan is the world's newest nation – it declared its independence on 9 Jul 2011. Israel was one of the first foreign nations to establish formal diplomatic ties with the fledgling Republic. Subsequently, Israel wasted no time in announcing publicly that all South Sudanese refugees would soon be required to leave; they were given a deadline of 31 Mar 2012, and were informed that they would be forcibly deported if still in Israel after that date.

Israel claims that, since having gained independence, it is now safe for South Sudanese nationals to return home. However, independent critics rebuke this, saying that there is still significant armed conflict between Sudan, South Sudan, and numerous rebel groups in the region. Aside from the ongoing security concerns, South Sudan is also one of the world's poorest and least-developed countries; claiming that South Sudan is ready to repatriate its people, is a ridiculous notion at best.

Israel helped formulate the UN Refugee Convention of 1951. This was in the aftermath of the Holocaust, an event in which millions of Jewish lives could have been saved, had the rest of the world accepted more European Jews as refugees. Israel, of course, is itself one of the world's most famous "refugee nations", as the majority of the nation's founders were survivors of Nazi persecution in Europe, seeking to establish a permanent homeland where Jews could forevermore seek shelter from oppression elsewhere.

It's ironic, therefore, that Israel – of all nations – until recently had no formal policy regarding asylum seekers, nor any formal system for managing an influx of asylum seekers. (And I thought Australia's handling of asylum seekers was bad!) To this day, Israel's immigration policy consists almost entirely of the Law of Return, which allows any Jew to immigrate to the country hassle-free.

Well, it seems to me that this law has recently been amended. For Jewish refugees, the Law is that you can Return to Israel (no matter what). For non-Jews, the Law is that you're forced to Return from Israel, back to wherever you fled from. Couldn't get much more double standards than that!

08
Jun

Introducing the Drupal Handy Block module

I've been noticing more and more lately, that for every new Drupal site I build, I define a lot of custom blocks. I put the code for these blocks in one or more custom modules, and most of them are really simple. For me, at least, the most common task that these blocks perform, is to display one or more fields of the node (or other entity) page currently being viewed; and in second place, is the task of displaying a list of nodes from a nodequeue (as I'm rather a Nodequeue module addict, I tend to have nodequeues strewn all over my sites).

In short, I've gotten quite bored of copy-pasting the same block definition code over and over, usually with minimal changes. I also feel that such simple block definitions don't warrant defining a new custom module – as they have zero interesting logic / functionality, and as their purpose is purely presentational, I'd prefer to define them at the theme level. Additionally, every Drupal module has both administrative overhead (need to install / enable it on different environments, need to manage its deployment, etc), and performance overhead (every extra PHP include() call involves opening and reading a new file from disk, and every enabled Drupal module is a minimum of one extra PHP file to be included); so, less enabled modules means a faster site.

To make my life easier – and the life of anyone else in the same boat – I've written the Handy Block module. (As the project description says,) if you often have a bunch of custom modules on your site, that do nothing except implement block hooks (along with block callback functions), for blocks that do little more than display some fields for the entity currently being viewed, then Handy Block should… well, it should come in handy! You'll be able to do the same thing in just a few lines of your template.php file; and then, you can delete those custom modules of yours altogether.

29
May

Introducing the Drupal Template Field Variables module

Drupal 7's new Field API is a great feature. Unfortunately, theming an entity and its fields can be quite a daunting task. The main reason for this, is that the field variables that get passed to template files are not particularly themer-friendly. Themers are HTML markup and CSS coders; they're not PHP or Drupal coders. When themers start writing their node--page.tpl.php file, all they really want to know is: How do I output each field of this page [node type], exactly where I want, and with minimal fuss?

It is in the interests of improving the Drupal Themer Experience, therefore, that I present the Template Field Variables module. (As the project description says,) this module takes the mystery out of theming fieldable entities. For each field in an entity, it extracts the values that you actually want to output (from the infamous "massive nested arrays" that Drupal provides), and it puts those values in dead-simple variables.

23
May

Flattening many-to-many fields for MySQL to CSV export

Relational databases are able to store, with minimal fuss, pretty much any data entities you throw at them. For the more complex cases – particularly cases involving hierarchical data – they offer many-to-many relationships. Querying many-to-many relationships is usually quite easy: you perform a series of SQL joins in your query; and you retrieve a result set containing the combination of your joined tables, in denormalised form (i.e. with the data from some of your tables being duplicated in the result set).

A denormalised query result is quite adequate, if you plan to process the result set further – as is very often the case, e.g. when the result set is subsequently prepared for output to HTML / XML, or when the result set is used to populate data structures (objects / arrays / dictionaries / etc) in programming memory. But what if you want to export the result set directly to a flat format, such as a single CSV file? In this case, denormalised form is not ideal. It would be much better, if we could aggregate all that many-to-many data into a single result set containing no duplicate data, and if we could do that within a single SQL query.

This article presents an example of how to write such a query in MySQL – that is, a query that's able to aggregate complex many-to-many relationships, into a result set that can be exported directly to a single CSV file, with no additional processing necessary.

10
May

Enriching user-entered HTML markup with PHP parsing

I recently found myself faced with an interesting little web dev challenge. Here's the scenario. You've got a site that's powered by a PHP CMS (in this case, Drupal). One of the pages on this site contains a number of HTML text blocks, each of which must be user-editable with a rich-text editor (in this case, TinyMCE). However, some of the HTML within these text blocks (in this case, the unordered lists) needs some fairly advanced styling – the kind that's only possible either with CSS3 (using, for example, nth-child pseudo-selectors), with JS / jQuery manipulation, or with the addition of some extra markup (for example, some first, last, and first-in-row classes on the list item elements).

Naturally, IE7+ compatibility is required – so, CSS3 selectors are out. Injecting element attributes via jQuery is a viable option, but it's an ugly approach, and it may not kick in immediately on page load. Since the users will be editing this content via WYSIWYG, we can't expect them to manually add CSS classes to the markup, or to maintain any markup that the developer provides in such a form. That leaves only one option: injecting extra attributes on the server-side.

When it comes to HTML manipulation, there are two general approaches. The first is Parsing HTML The Cthulhu Way (i.e. using Regular Expressions). However, you already have one problem to solve – do you really want two? The second is to use an HTML parser. Sadly, this problem must be solved in PHP – which, unlike some other languages, lacks an obvious tool of choice in the realm of parsers. I chose to use PHP5's built-in DOMDocument library, which (from what I can tell) is one of the most mature and widely-used PHP HTML parsers available today. Here's my code snippet.

21
Apr

Argentina: ¿que onda?

A few days ago, Argentina decided to nationalise YPF, which is the largest oil company operating in the country. It's doing this by expropriating almost all of the YPF shares currently owned by Spanish firm Repsol. The move has resulted in Spain — and with it, the entire European Union — condemning Argentina, and threatening to relatiate with trade sanctions.

This is the latest in a long series of decisions that Argentina has made throughout its modern history, all of which have displayed: hot-headed nationalist sentiment; an arrogant and apathetic attitude towards other nations; and utter disregard for diplomatic and economic consequences. As with previous decisions, it's also likely that this one will ultimately cause Argentina more harm than good.

I think it's time to ask: Argentina, why do you keep shooting yourself in the foot? Argentina, are you too stubborn, are you too proud, or are you just plain stupid? Argentina, ¿que onda?